From 2009: Here’s math that even Bart Simpson won’t need a chalkboard to figure out: “The Simpsons” is “Gunsmoke.” That’s right: thanks to a new two-year renewal, “The Simpsons” is about to blow past the ancient western as the longest-running primetime series in American television history. And my guest today, “Simpsons” executive producer Al Jean, has been there for every episode—plus a feature-length movie.